As with anything you must train and practice to achieve proficiency. If you don't practice drawing and firing your weapon when the time comes, you will fail. Firearms do not fire them selves and will not hit what they are not pointed at.
You do have the right to keep and bear arms but this comes at a price.
It is your responsibility to make sure that your weapon will fire when needed.
It is your responsibility to make sure that when you fire your weapon that you hit your target.
It is your responsibility to make sure that your weapon is stored in a safe place. It is your responsibility to train, train, train.